Publications

2011

• Nonlinear fluid-structure interaction problem. Part I: implicit partitioned algorithm, nonlinear stability proof and validation examples
  
  • Kassiotis Christophe
  • Ibrahimbegovic Adnan
  • Niekamp Rainer
  • Matthies Hermann G.
  Computational Mechanics, Springer Verlag, 2011, 47, pp.305-323. In this work we consider the fluid-structure interaction in fully nonlinear setting, where different space discretization can be used. The model problem considers finite elements for structure and finite volume for fluid. The computations for such interaction problem are performed by implicit schemes, and the partitioned algorithm separating fluid from structural iterations. The formal proof is given to find the condition for convergence of this iterative procedure in the fully nonlinear setting. Several validation examples are shown to confirm the proposed convergence criteria of partitioned algorithm. The proposed strategy provides a very suitable basics for code-coupling implementation as discussed in Part II. (10.1007/s00466-010-0545-6)
  DOI : 10.1007/s00466-010-0545-6
• TELEMAC: An efficient hydrodynamics suite for massively parallel architectures
  
  • Moulinec Charles
  • Denis Christophe
  • Pham C.-T.
  • Rougé D.
  • Hervouët Jean-Michel
  • Razafindrakoto Emile
  • Barber R. W.
  • Emerson D. R.
  • Gu X. J.
  Computers and Fluids, Elsevier, 2011, 51 (1), pp.30-34. This paper investigates the use of TELEMAC (a Finite Element-based hydrodynamics suite) on massively parallel computer architectures. The performance of TELEMAC is illustrated using two separate test cases. The first considers the use of TELEMAC-2D for simulating tidal currents in the vicinity of a renewable energy marine turbine farm, in order to provide reliable estimates of the expected energy yield. The second demonstrates the use of TELEMAC-3D for assessing the effects of fresh water discharges on the salinity distribution in a coastal lagoon. The simulations have been performed with meshes ranging from 2 to 12 million elements, and good scaling performance is achieved on a variety of different computer architectures. (10.1016/j.compfluid.2011.07.003)
  DOI : 10.1016/j.compfluid.2011.07.003
• Multilayer Saint-Venant Equations over movable beds
  
  • Audusse Emmanuel
  • Benkhaldoun Fayssal
  • Sainte-Marie Jacques
  • Seaid M.
  Discrete and Continuous Dynamical Systems - Series B, American Institute of Mathematical Sciences, 2011, 15 (4), pp.917-934. We introduce a multilayer model to solve three-dimensional sediment transport by wind-driven shallow water flows. The proposed multilayer model avoids the expensive Navier-Stokes equations and captures stratified horizontal flow velocities. Forcing terms are included in the system to model momentum exchanges between the considered layers. The topography frictions are included in the bottom layer and the wind shear stresses are acting on the top layer. To model the bedload transport we consider an Exner equation for morphological evolution accounting for the velocity field on the bottom layer. The coupled equations form a system of conservation laws with source terms. As a numerical solver, we apply a kinetic scheme using the finite volume discretization. Preliminary numerical results are presented to demonstrate the performance of the proposed multilayer model and to confirm its capability to provide efficient simulations for sediment transport by wind-driven shallow water flows. Comparison between results obtained using the multilayer model and those obtained using the single-layer model are also presented. (10.3934/dcdsb.2011.15.917)
  DOI : 10.3934/dcdsb.2011.15.917
• Nonlinear fluid-structure interaction problem. Part II: space discretization, implementation aspects, nested parallelization and application examples
  
  • Kassiotis Christophe
  • Ibrahimbegovic Adnan
  • Niekamp Rainer
  • Matthies Hermann G.
  Computational Mechanics, Springer Verlag, 2011, 47, pp.335-357. The main focus of the present article is the development of a general solution framework for coupled and/or interaction multi-physics problems based upon re-using existing codes into software products. In particular, we discuss how to build this software tool for the case of fluid-structure interaction problem, from finite element code Feap for structural and finite volume code OpenFOAM for fluid mechanics. This is achieved by using the Component Template Library (CTL) to provide the coupling between the existing codes into a single software product. The present CTL code-coupling procedure accepts not only different discretization schemes, but different languages, with the solid component written in Fortran and fluid component written in \Cpp. Moreover, the resulting CTL-based code also accepts the nested parallelization. The proposed coupling strategy is detailed for explicit and implicit fixed-point iteration solver presented in the Part I of this paper, referred to Direct Force-Motion Transfer/Block-Gauss-Seidel. However, the proposed code-coupling framework can easily accommodate other solution schemes. The selected application examples are chosen to confirm the capability of the code-coupling strategy to provide a quick development of advanced computational tools for demanding practical problems, such as 3D fluid models with free-surface flows interacting with structures. (10.1007/s00466-010-0544-7)
  DOI : 10.1007/s00466-010-0544-7
• Clapage de sédiments non-cohésifs sous courant : simulations versus expérimentations
  
  • Nguyen Duc Hau
  • Guillou Sylvain
  • Nguyen Kim Dan
  • Pham van Bang Damien
  , 2011, pp.233-236. La maintenance des chenaux de navigation et des zones portuaires implique la réalisation d’opérations de dragage. Les produits de dragages sont souvent déposés en mer (opération de clapage) pouvant induire des nuisances sur l’environnement. Le phénomène de clapage comporte principalement trois phases (BOUTIN, 2000) : la phase de chute (soumise aux courants) ; l’impact sur le fond et la génération d’un courant de densité ; la propagation des courants de densité et la décantation des sédiments. Nous simulons ce phénomène à l’aide d’un modèle à deux phases adapté aux milieux denses en différentiant les deux constituants. Les études sur le clapage avec ce modèle ont démarré dans un cas sans courant (GUILLOU et al., 2011). Les travaux présentés ici portent sur une étude systématique de la dynamique de chute et de transport en fonction du courant relative à la configuration expérimentale utilisée par VILLARET et al. (1998). (10.5150/cmcm.2011.050)
  DOI : 10.5150/cmcm.2011.050